1. Field of the Invention
The present invention relates to a magnetic coupling assembly, and more particularly to a magnetic coupling assembly to adjust an air gap between two disks with piezoelectric actuators.
2. Description of Related Art
An axial coupling assembly is mounted between a driving element and a driven element to transmission power from the driving element to a driven element. A magnetic coupling assembly is a non-contact coupling assembly and comprises a permanent magnet disk and a magnetically conductive disk spaced from each other to form an air gap between the disks. When the air gap between the disks is adjusted, the magnetic force applied to the magnetically conductive disk from the magnetic disk is changed and the transferring torque of the coupling assembly is also changed to fit with different needs. To adjust the air gap between the disks, an adjusting device is arranged. The conventional adjusting device is mechanical and may include a manual operation type and an auto operation type. In the manual operation type, a mechanism, such as a gear set is provided to enable a user to adjust the air gap manually with the transmission of the mechanism. However, the operation of the conventional manual operation typed adjusting device is laborious and inconvenient in use. In the auto operation type, a motor is provided to serve as a power source so that the air gap can be adjusted automatically. However, the motor has to keep rotating for keeping the air gap in a desired width, the conventional auto operation typed adjusting device is also inconvenient in use.
U.S. Pat. No. 6,682,430, entitled to “Adjustable Magnetic Coupler”, provides a push-pull means to move magnet rotors axially and to adjust the width of an air gap. The push-pull means of the '430 patent comprises a mechanism linked between rotors for moving a magnet rotor in response to movement of a magnet rotor and having a link and a swing unit. However, a large driving force is necessary for the operation of the mechanical push-pull means of the '430 patent, and to lubricate the push-pull means of the '430 is difficult. In addition, high heat will generate during the operation of the magnetic coupler of the '430 patent.
To overcome the shortcomings, the present invention tends to provide a magnetic coupling assembly to mitigate or obviate the aforementioned problems.